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Edward
Edward, Service Technician
Category: Jeep
Satisfied Customers: 3023
Experience:  20 + years experience on various makes and models.
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I have a 200o jeep cherokee. It will crank but not start. I

Customer Question

I have a 200o jeep cherokee. It will crank but not start. I can get it to start using starting fluid and it runs fine. The only other thing is the alternator will not charge . have taken it off and it test fine. Looks like it not getting the necessary signal to engage the charging. They may be related but not sure.
JA: Have you checked the fuel supply? And are all the spark plugs working?
Customer: did you read my response. it starts and runs on starting fluid.
JA: What year is your Cherokee?
Customer: can you read
JA: Are you fixing your Cherokee yourself? What have you tried so far?
Customer: .
JA: Anything else you want the mechanic to know before I connect you?
Customer: ,
Submitted: 3 months ago.
Category: Jeep
Expert:  John Taylor replied 3 months ago.

Hello, My name is***** am a Chrysler Master Technician.

Sounds as if you may have a bad crankshaft position sensor. Is the check engine light on when it is running? Please be very careful using starting fluid in a gasoline engine, it can cause detonation and ruin your engine.

Customer: replied 3 months ago.
I replaced the crankshaft position sensor with a mopar part. I don't think it would run and start on starting fluid if was bad but I changed it out
Expert:  John Taylor replied 3 months ago.

We will have to do some tests to see what is causing it not to start on its own.

First test i would like you to try is to go into the fuse block under the hood, and look for the ASD Relay. Swap that one with the horn relay, and attempt to start the vehicle.

Customer: replied 3 months ago.
Changed out relay still no start
Expert:  John Taylor replied 3 months ago.

Ok, lets try looking at the fuel side. Swap the horn relay and the fuel pump relay, see if the vehicle will start. This is a odd issue, so bear with me, we have to check the simple stuff first.

If you swap that relay and it doesnt start, we need to check the fuel pump module. You should hear the fuel pump actuate when you turn the key to the on position. should sound like a "whir" coming from the back of the vehicle.

I understand it runs on starting fluid, but i am thinking maybe it is drawing fuel on its own after it gets started. Have you driven the vehicle after it was started with starting fluid?

Expert:  John Taylor replied 3 months ago.

Also make sure you have checked all fuses in the fuse block under the hood. You will need a test light to verify. If those are all good, we need to check and see if we have power at the fuel pump module connector. Key on, probe the connector with the test light and see if you have power.

Customer: replied 3 months ago.
I have not driven after starting since the alternator is not charging I will get the battery up on it tonight and try that tomorrow evening. Where is the module located on the fuel pump. I can hear it buzz with key on. I also have pressure in the rail. If I bleed it off it builds back up. One other odd thing if I unplug the ecu over night it will start one time on its own but never a second time
Expert:  John Taylor replied 3 months ago.
I am wondering if the skim (security) module has failed. It will not start if it has lost the secret key. If you can give me the last 8 of the vin, I can check in the morning for you.
Customer: replied 3 months ago.
Yl220719
Expert:  John Taylor replied 3 months ago.

Ok give me one min.

Expert:  John Taylor replied 3 months ago.

Be advised, you have a open recall on your vehicle.

Expert:  John Taylor replied 3 months ago.

The skim seems to be working because it will let you spin the starter over, and it will run without killing the engine after 2 seconds.

We need to check and make sure the pcm is getting the ignition feed signal

Expert:  John Taylor replied 3 months ago.

We need to check pin number 22 with a test light, see if it lights up with the key on.

Disconnect the black connector (c1) and check the pin in relation to the diagram.

Customer: replied 3 months ago.
Have 12.4 continuous with key to on position
Expert:  John Taylor replied 3 months ago.

Ok, that means the pcm is getting the proper feed it needs. This one is stumping me, lets try one more thing before I opt out and let another expert try to help you.

Since you are saying it starts and runs fine on starting fluid, it is getting fuel and spark. But seems something is messing with the staring injector pulse width maybe. The pcm will look at the MAP sensor as the primary input for the starting equation (speed density), it could be that the map is sending a scewed signal. Try disconnecting the map sensor and see if it will start in default.

Expert:  John Taylor replied 3 months ago.

here is the location of the map sensor on the throttle body

Customer: replied 3 months ago.
Still no luck on starting
Expert:  John Taylor replied 3 months ago.

Ok bud, i will opt out and see if someone else can help you. Have a good day!

Expert:  Edward replied 3 months ago.

Can you tell me if you have power to one of the wires at any fuel injector with key ON? thanks.

Customer: replied 3 months ago.
Ok here's what I have
Key on zero
First crank and start 12.2
Key off start retry 10.4If I wait for some period of time I can repeat
Expert:  Edward replied 3 months ago.

So when cranking does it hit at all and try to start? and no power to any fuel injector with key ON is a problem, but I'm wondering since you have power in START position if indeed it tries to fire up and run and then dies as soon as you turn the key back to the ON position.

Customer: replied 3 months ago.
After it set for some time it starts. Turn the vehicle of and retry and only the starter engages but does not try to start which is evident with low voltage to injectors but will start and run with starting fluid but alternator does not charge
Expert:  Edward replied 3 months ago.

Is this regular cherokee or grand cherokee? and does it have a 4.0 L straight 6 cylinder in it? thank you.

Customer: replied 3 months ago.
Regular Cherokee 4.0l
Expert:  Edward replied 3 months ago.

Here is the diagram of how the injectors get power, the ASD relay powers them up with key ON. The ECM (engine computer) grounds the ASD relay with the key on, Check all those fuses up top in this diagram, make sure they all have power to them and are good, and pull the ASD relay out and see if you have 2 pins in the ASD relay socket HOT with the key ON. the BLUE/YELLOW wire running to the ASD relay grounds the relay and it's ground comes from pin 3 and the ECM.

Customer: replied 2 months ago.
Here's what I have. Standing in front of the jeep looking for the back at the ASD relay position 12 clockwise key off zero voltage Position 3 12.5 position 6 zero position 9 zero checking the ohm at position 12 1.7m position 3 zero position 6 170 position nine 36k. Key on position 12 zero voltage position three 12.11 position six 11.88 position 9 zero Ohms position 12 1.82m position 3 zero position six Zero position nine 38k
Expert:  Edward replied 2 months ago.

So there is only one hot pin with 12 volts with the key ON at the ASD relay socket? correct?

Customer: replied 2 months ago.
Position 3 and 6 had voltage 12.11 and 11.88
Expert:  Edward replied 2 months ago.

Alright, that's correct. and with the key ON, per the diagram, the ASD relay powers up fuse 18 and fuse 21. So check those two fuses with key ON and they both should have power. fuse 18 and 21 both are 15 amp fuses.

Customer: replied 2 months ago.
There are several 15 amp fuses do I don't see any markings
Customer: replied 2 months ago.
They all have 12 volts
Expert:  Edward replied 2 months ago.

but you have no 12 volts at the fuel injector when the key is in START position still correct?

Customer: replied 2 months ago.
still do
Expert:  Edward replied 2 months ago.

Alright, let me opt out so another expert can assist. I can't be online tom. and I don't want you to wait, I will check back later and see what progress is made. thank you.

Customer: replied 2 months ago.
Ok thank going to have it towed to dealer I don't have anymore time to wait